jb5000
There will be very few cases where you can do what is called a "precautionary landing" (forced down by weather or lack of fuel) in a field and then take off again on your own.
Such a landing is normally going to be a major hassle. Some fields one can take off from (need to establish the distance, check for potholes etc) but the recovery will usually be done by someone competent; not a fresh PPL.
Most of the cases that do happen (I am talking about Cessna/Piper spamcans, not microlights) need the wings taken off and the thing carted back on a trailer; the cost is a few grand and the aircraft owner will really love you for having done that... especially as few maintenance shops know how to correctly rig an aircraft so it probably won't fly the same way again.
With helicopters it's easy of course
Far better to make an early decision and land somewhere proper. Any passengers may not be happy about that of course (might have to make complicated urgent arrangements for babysitting etc) and it could be a huge hassle and many won't fly with you again, but that's what flying without an IFR option is like! You've got to stick to nice days and short trips.